Various mailing systems and methods have been employed in the past for receiving materials from a number of sources and collating the materials, or combining them into a single packet of material. The single packet is then inserted into an envelope at an envelope inserting station located further downstream.
In known mailing systems, the prime document is typically generated or fed and additional materials are added to the prime document as it traverses the mail processing system. Typically, the packet is comprised of a single stack of documents, wherein the order of the documents in the stack is predetermined by the process flow of the mail processing system.
Known track systems feed documents from a series of feed stations in a synchronized manner so that a document from each feed station is placed on top of a document from a preceding, up-stream feed station. A number of documents are collated together to form a packet and at the end of the track the packet is inserted into an envelope. Usually the packet of documents comprises one prime document, such as an address bearing document, and several attachments, such as leaflets or advertisements. The prime document includes the mailing address to which the package (e.g. envelope with packet inserted therein) is to be delivered and the collating must be done so that when the documents are placed in a window envelope, the address will be visible through the window. This process can be done by first feeding the prime document onto the track conveyor, face downwards, and adding the subsequent documents on top to form a packet which is then inserted into the envelope with the prime document facing downwards.
U.S. Pat. No. 4,753,429 discloses a synchronous system that uses two fixed pins of different heights and provides a method of collation for two subsets of documents into a single packet. With this system, the document which is to be placed on top of the packet must be transported by the first (shorter) set of pins in the synchronous transport.
In U.S. Pat. No. 6,915,184, a document collator includes a conveyor system, a prime document feeder station and a plurality of enclosure document feeder stations arranged at spaced locations along the conveyor system. The collator is a non-synchronous system that allows the order of a collation to be varied within a mail processing system by sequencing the order in which the documents are fed.
Accordingly, there remains room for improvement in the art for a synchronous collating apparatus and method for merging a plurality of document sets into a single set, in any desired order.